1. Field of the Invention
This invention relates to a composition for use in a refrigeration cycle, particularly a composition for a refrigeration cycle using a hydrofluorocarbon type refrigerant, and a refrigerating apparatus using the composition.
2. Description of the Related Art
The use of such chlorine-containing Flons as dichlorodifluoroethane (hereinafter referred to as "CFC12"), monochloro-difluoromethane (hereinafter referred to as "HCFC22"), and R-502 which is an azeotropic mixture of HCFC22 with CFC115 will be banned because they have been established as refrigerants which are associated with the depletion of the ozonosphere. As prospective alternatives to these Flons, such hydrofluorocarbon type refrigerants as difluoromethane (hereinafter referred to as "HFC32"), pentafluoroethane (hereinafter referred to as "HFC125"), 1,1,1,2-tetrafluoroethane (hereinafter referred to as "HFC134a"), 1,1,1-trifluoroethane (hereinafter referred to as "HFC143a"), and 1,1-difluoroethane (hereinafter referred to as "HFC152a") which avoid depleting the ozonosphere have been being studied for their feasibility as simple compounds or mixtures. Meanwhile, the development of a refrigerating apparatus which operates by the use of this hydrofluorocarbon type refrigerant has been being urged.
The refrigerating apparatus is represented by an air conditioner, a refrigerator, or the like which incorporates therein a refrigeration cycle consisting of the four actions, i.e. evaporation, compression, condensation, and expansion. In the refrigeration cycle, the refrigerant is circulated while repeating changes from liquid to gas and gas to liquid. The refrigeration cycle has further contained in the system thereof a refrigerator oil and a desiccating agent. The refrigerator oil is used herein particularly for lubrication in the compression mechanism part. For the sake of the return of the oil within the cycle, the refrigerator oil is required to manifest compatibility with the refrigerant as an indispensable property. Since the aforementioned alternative Flons show practically no solubility to the mineral oil heretofore used as the refrigerator oil, the feasibility of such refrigerator oils as polyol ester type oils and polyether type oils which show solubility to the hydrofluoro-carbon type refrigerant is now being studied. The prospective refrigerator oils include polyalkylene glycol oils and polyalkyl benzene type oils as well.
The drier is packed with the desiccating agent and then disposed in the refrigeration cycle for eliminating water from the cycle.
As the desiccating agent, the sodium A type zeolite which is designated as the 4A type has been heretofore used in the refrigeration cycle which comprises CFC12, R-502, and the HCFC22 type refrigerant and a mineral oil.
The alternative Flons mentioned above and such refrigerator oils as polyester type oils and polyether type oils share the quality of high absorbency and possibly entail entrance of a large volume of water into the refrigeration cycle. This entrance of water opens up the possibility that the water will freeze inside the capillary tube and will consequently induce hydrolysis of the refrigerant and the refrigerator oil, deterioration of the materials forming the system with an acid component produced inside the cycle, and occurrence of oil slags. For the refrigeration cycle which uses an alternative Flon and a polyester type oil or a polyether type oil which fits the alternative Flon, therefore, the removal of this water constitutes itself an important task.
When the conventional sodium A type zeolite is used in the refrigeration cycle using an alternative Flon for the purpose of lowering the water concentration in the cycle, however, the refrigeration cycle will be at a disadvantage in incurring decomposition of the Flon which is formed solely of HFC32 or of a mixture containing HFC32 and, at the same time, exerting an adverse effect also on the A type zeolite, and eventually failing to attain sufficient removal of the water.